Professor Tom Constantine, the former director of the US Drug Enforcement Administration, is the person who will oversee changes to the Northern Ireland police force.

Mr Constantine, 61, is also the former chief of police for New York State.

His reputation for dealing with drug dealers in the city led to his name being given to an organisation dedicated to educating children about drugs and respect for the law, Constantine's Circus.

Writing on its website, the organisation's founder, Terry O'Neill, says of Prof Constantine: "He's my teacher. That makes him my biggest and strongest and best friend."

Policing career

Tom Constantine was born in 1938 Buffalo, New York, of Irish-American descent with family roots in County Clare.

His approach to policing may have originated in the mists of time - the Constantine's Circus website describes him as a descendant of Constantine O'Brien, a 12th century Irish warrior.

Mr Constantine's policing career began in 1960 with the Erie County Sheriff's Department.

He recalled: "At that time, law enforcement was a chance for people of my generation, usually people of ethnic groups - Irish, Italian, Polish - who grew up in city neighbourhoods, and who had not gone to college, to get into an occupation with a challenging environment that had a good deal of flexibility and autonomy.

"We were looking for excitement and adventure."

He joined the New York State Police in 1962 and rose through the ranks to become the city's police superintendent by 1986.

During this period, he is said to have turned the force into an effective drug-fighting unit and was credited with a string of successful operations against trafficking.

In 1994, President Clinton named him the new head of the Drug Enforcement Administration, responsible for the US's national and international fight against narcotics.

Retirement

Mr Constantine announced that he was retiring from the DEA for personal reasons in July 1999 - but not without having differed from the Clinton administration on drugs policy.

Testifying to the US Senate earlier that year, he said that Mexico posed the worst criminal threat to the US because of the failure to tackle the flow of drugs through its territory - despite White House policy which regards the neighbouring state as an ally in the war on drugs.

But his efforts to law enforcement were nationally recognised when he joined only a handful of people ever to be named an honorary FBI agent.

In September 1999 New York State University appointed him Professor of Public Service at Rockefeller College where he has been working on continuous learning programmes for criminal justice professionals such as police officers.

Mr Constantine's work in Northern Ireland has already begun.

He will monitor how reform of the Royal Ulster Constabulary is carried out in line with legislation currently going through Parliament.

He has been appointed for a three-year term, after which the post will be reviewed.